I know how hard it is to be in a situation where you really can't do anything... it is often said that it is during times like these that God teaches you to really trust in Him. The one thing you can do is also the best and most important thing you can do... pray! Keep praying for your husband, your father in law, and for yourself... pray for the people that God is using to treat and take care of them. And as you pray... believe! Believe that God is making your husband and father in law better... believe that you will all be together again, full of joy and love... believe that God is giving you the strength and peace to get through each day until you are all together again.
And if it gets hard to believe and have faith... just tell our Lord Jesus and ask Him to bless you with more faith. He is faithful... every day and in every way.
I will be praying for you.